Abstract

We propose a new mathematical model for relative collision safety in cars. Our present research is restricted to head-on crashes between two cars and we try to determine how much of the injury risk in a crash depends on the car make. Previous work shows that a person’s age and sex influence the injury risk in accidents that are otherwise similar. To explore the relative risks between different car makes we build a model where we let the car mass, change of speed, design of the car and the driver’s age and sex explain the injury outcome in the crashes. The mathematical model we use is a birth process where the states correspond to the injury classes. A database containing police reported traffic accidents and hospital information is used to explore the relationships in our model. Different models are compared and the “best” model is chosen by a likelihood ratio test. The estimated relative risks compensated for the driver’s age and sex are compared to the relative risks with the driver population included. The uncertainties of the different estimates are studied by a bootstrap analysis.

Author Keywords: Relative collision safety; Driver characteristics; Birth process; Bootstrap; Confidence intervals; Estimation; Maximum likelihood

Article Outline

1. Background

1.1. Introduction

1.2. Physical background

1.3. Description of our database

2. Model formulation

3. The effect of driver characteristics

3.1. Including age and sex

4. Estimation method

4.1. Introduction

4.2. Four-step maximum likelihood method

5. Estimation results

6. Uncertainty analysis

6.1. Introduction

6.2. Bootstrap analysis

7. Summary

References